This invention relates to a novel process for preparing 2-halogeno-3-hydroxy-3-phenylpropionic acid ester compounds.
Optically active 2-halogeno-3-hydroxy-3-phenylpropionic acid ester compounds are important compounds as intermediates of diltiazem hydrochloride which is useful as a coronary vasodilating agent and other various pharmaceutical compounds.
In the prior art, as the process for preparing 2-halogeno-3-hydroxy-3-phenylpropionic acid ester compounds, there has been known the method in which a halogenoacetic acid ester compound and a benzaldehyde compound are permitted to react in the presence of an optically active lithium amide compound and alkyl lithium to give the above ester compounds (Japanese Unexamined Patent Publication NO. 226881/1989).
However, this process employs an expensive optically active reagent to effect asymmetric induction, when reacting the halogenoacetic acid ester compound and the benzaldehyde compound. Thus, there has been demanded a process for preparing 2-halogeno-3-hydroxy-3-phenylpropionic acid ester compounds by using an enzyme in place of an expensive optically active reagent.